Externet Posted May 20, 2022 Share Posted May 20, 2022 Was trying to find hardness figures for nylon, delrin, ABS, teflon, poliethylenes ... and got lost in too many scales Shore, Brinnell flavors, Vickers, Rockwell, and metric and not metric,  Is so much variety needed ? No consensus ? Very nasty to see so many and looking for the proper conversion.  😱 Link to comment Share on other sites More sharing options...
TheVat Posted May 20, 2022 Share Posted May 20, 2022 I only know the one geologists use, the Mohs.  Though named for a German fellow, his surname also provides the perfect mnemonic (in English) for recalling it....MOHS, measure of hardness scale. Link to comment Share on other sites More sharing options...
studiot Posted May 20, 2022 Share Posted May 20, 2022 16 hours ago, Externet said: Was trying to find hardness figures for nylon, delrin, ABS, teflon, poliethylenes ... and got lost in too many scales Shore, Brinnell flavors, Vickers, Rockwell, and metric and not metric,  Is so much variety needed ? No consensus ? Very nasty to see so many and looking for the proper conversion.  😱 That may be because hardness is a much less well defined concept, especially for ductile materials and even more especially for very ductile materials such as plastics. Is the required information for machine workability ? Link to comment Share on other sites More sharing options...
Externet Posted May 20, 2022 Author Share Posted May 20, 2022 Thanks. Yes, I need a part made and wanted to have a sense of which material would be convenient. I do not know if hardness is what I have to look for. 'Deformability' plus 'resiliency' to act as a seal/gasket between surfaces would make more sense 🤔  Gathering several different materials to evaluate how they perform under 5000 psi after CNC machined. Link to comment Share on other sites More sharing options...
StringJunky Posted May 21, 2022 Share Posted May 21, 2022 Have a look at Vespel, but it's very expensive. https://en.wikipedia.org/wiki/Vespel#:~:text=Vespel is mostly used in,hostile and extreme environmental conditions. Link to comment Share on other sites More sharing options...
studiot Posted May 21, 2022 Share Posted May 21, 2022 (edited) 11 hours ago, Externet said: Thanks. Yes, I need a part made and wanted to have a sense of which material would be convenient. I do not know if hardness is what I have to look for. 'Deformability' plus 'resiliency' to act as a seal/gasket between surfaces would make more sense 🤔  Gathering several different materials to evaluate how they perform under 5000 psi after CNC machined. Deformability is not a very well defined concept either. You listed a some 'plastics' materials. Plastics as a collective term are renowned for their long term deformability. Continued unrecoverable deformation over time is called plastic behaviour and the result is called creep. A seal that slowly squashes is of no long term use. Soft copper for instance squashes once and stays that way. It also has a higher upper and lower temperature working range.  But if this is critical you really need expert advice. Edited May 21, 2022 by studiot Link to comment Share on other sites More sharing options...
John Cuthber Posted May 21, 2022 Share Posted May 21, 2022 I have used PEEK fittings at 5000 PSI and above. Â Â Link to comment Share on other sites More sharing options...
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